Beginning in the 1950s and early 1960s, the foaming of streams, rivers, and some lakes was a condition widely noted as approaching an ecological crisis in the United States. Today the Environmental Protection Agency estimates that 25% of the nation's lakes are polluted and another 20% are threatened. The Senate Majority Leader has recently announced he plans to introduce legislation aimed at increasing the protection of fresh water lakes, including the elimination of the use of phosphates in detergents. Lakes become cloudy when excessive phosphate pollution from detergents and agriculture boosts the growth of algae. Although phosphates account for only a small percentage of phosphorous emissions overall in the United States, detergent phosphorous is a much more significant percentage in some highly populated areas.
The first bans on phosphates in detergent occurred in the Great Lakes region in the 970s when Lake Erie, in particular, was choked with pollution. Most recently, Pennsylvania has been acting to regulate phosphates.
The best selling book 50 Simple Things You Can Do To Save The Earth recommends the use of a low-phosphate or phosphate-free detergent and mentions that liquid detergents are generally phosphate-free. In the United States, bans on the use of sodium tripolyphosphate (STPP) have boosted sales of phosphate-free detergents to a significant share of the domestic market; however, phosphate continues to be the leading "builder" in U.S. and European detergent production.
Detergent builders are substances that increase the effectiveness of surfactants and typically act as water softeners and as sequestering and buffering agents. Because phosphates are excellent, inexpensive builders, replacing phosphates has posed difficulties, particularly for certain applications and for dry cleaning compositions. For example, although there are a number of patents that have issued since the later 1970s describing various non-phosphate automatic dishwasher detergent compositions, commercial acceptability has not followed, due perhaps to inadequate cleaning performances provided by these alternate compositions. Also, increased production expense and stability problems for granulated, nonphosphate compositions have been encountered.
U.S. Pat. Nos. 3,825,498, issued Jul. 23, 1974, 4,203,858, issued May 20, 1980, and 4,539,144, issued Sep. 3, 1985, describe dishwashing compositions that include specific polymers or polymers in particular amounts as replacements for phosphates. Thus, the U.S. Pat. No. 35 3,825,498 (inventors Altenschopfer et al.) describes a dishwashing detergent composition that includes 5-90% by weight of a solid crosslinked or noncrosslinked hydroxycarboxylic acid polymer and that is said to have a particularly strong cleaning effect against protein containing burnt scraps of food. U.S. Pat. No. 4,203,858 (inventor Chakrabarti) describes a dishwashing composition that includes a polyelectrolyte salt with a molecular weight between about 500-4,000 and that is said to be phosphate-free and low foaming. U.S. Pat. No. 4,539,144 (inventors de Ridder et al.) describes a dishwashing composition with a small amount of hydrolyzed polymaleic anhydride having an average molecular weight of about 2500, which is said to have improved non-foaming, non-spotting, or non-streaking properties.
U.S. Pat. Nos. 3,941,710, issued Mar. 2, 1976, 4,049,585, issued Sep. 20, 1977, and 4,127,496, issued Nov. 28, 1978, all describe low or antifoaming surface active agents, typically non-ionic for inclusion in cleaning compositions. Thus, U.S. Pat. No. 3,941,710 (inventors Gilbert et al.) describes use of a specific type of anionic surfactant (polyether carboxylate) with a non-ionic surface active agent. These surfactants are described for use with an antifoaming agent of a fatty acid phosphate or certain fatty acids and together are said to permit the reduction of phosphate content to not more than 15 percent. U.S. Pat. No. 4,049,585 (inventor Heckert) discloses use of vicinal non-terminal disulfates as low sudsing surfactants useful in automatic dishwashing compositions containing a low amount of conventional sequestering builders such as phosphates. U.S. Pat. No. 4,127,496 (inventor Stokes) describes uses of non-ionic detergents with either tetrasodium ethylenediamine tetracetate or nitrilotriacetic acid. However, the latter, while an effective builder, has been implicated in possible carcinogenicity.
U.S. Pat. No. 4,162,987, issued Jul. 31, 1979, inventors Maguire, Jr. et al., describes automatic dishwashing compositions with a binary enzyme system comprising a proteolytic enzyme and an amylolytic enzyme. Polyphosphates are suggested for inclusion as builders in the compositions.
U.S. Pat. No. 4,576,727, issued Mar. 18, 1986, inventor Browne, discloses phosphate-free detergent compositions for textile washing and notes that replacements of the customary tripolyphosphate builders have been unsatisfactory for one reason or another, with replacement by sodium citrate requiring such a large amount, particularly for high temperature washing, that the costs would be unacceptable.